In the prior art a method of aligning molecules of a liquid crystal material in a chosen direction involves the step of rubbing the surface of an electrode film on a substrate in a chosen direction with a rubbing cloth. The rubbing causes the material of the surface of the electrode film on the substrate to be oriented into the chosen direction. When a liquid crystal material is placed on the rubbed electrode film, the molecules of the liquid crystal material are sympathetically aligned in the direction of rubbing of the electrode film. A liquid crystal display cell, which has two electrode films which are rubbed in perpendicular directions, is also known in the prior art.
In the present invention a thin alignment film whose film growth is orientated by vacuum deposition in a given direction is formed on an electrode film. The thin alignment film will, according to present theory, sympathetically align liquid crystal molecules of a liquid crystal material, when said liquid crystal material is placed on said thin alignment film. The thin alignment film is grown in a desired direction by vacuum depositing material on the electrode film from a large angle relative to the normal of the electrode film. Two such thin alignment films may be used on two electrode films of a liquid crystal display cell to form a polarizing liquid crystal display cell.
The method of the present invention given more consistent and predictable alignment results than the prior art method. The rubbing method of the prior art is pressure sensitive and not easily reproducible whereas the alignment film of the present invention is more reproducible due to the use of vacuum deposition which may be accurately controlled.